The invention relates to a mount for limiting the transmission of vibratory disturbances, and more specifically the invention relates to a mount wherein the mount includes a unitary member that serves as a load carrying spring and damper.
Generally, mounts or isolation devices are used to limit the transmission of vibratory disturbances from a first vibrating structure to a second supported structure.
It is desirable for such mounts to provide effective damping over large deflections and over a wide range of frequencies. One way that prior art mounts accommodate such a range of loads and deflections is by including a discrete load carrying spring member in combination with a discrete damper. Such prior art mounts that provide a spring and damper and are modular in design and assembly. The discrete load carrying spring is made from a highly resilient elastomer such as natural rubber and the discrete damper is made from a material that experiences high hysteresis or is lossy and such material may comprise polybutadiene. When assembled the discrete damper and spring are aligned along a working axis. The spring and damper are typically comprised of a large number of discrete component parts that must be assembled precisely and with the proper axial alignment. Due to the large number of component parts and because of the precise alignment required to manufacture and assemble such prior art mounts, the mounts are difficult and expensive to manufacture and assemble.
The foregoing illustrates a limitation known to exist in present mounts. Thus, it is apparent that it would be advantageous to provide an alternative directed to overcoming the limitation set forth above. Accordingly, a suitable alternative mount is provided including features more fully disclosed hereinafter.
In one aspect of the present invention this is accomplished generally by providing a mount with a unitary member that serves both as a load carrying spring and provides damping. More specifically the mount of the present invention comprises a unitary resilient member, where said unitary resilient member comprises a spring portion, a damping layer and an intermediate stiffening portion joining the spring portion and damping layer, said resilient member being compressible and extendible. The mount also comprises a casing substantially enclosing said unitary resilient member; and damping force means located in contact with said damping layer, the damping means providing damping in response to compression and extension of said resilient member.
The unitary resilient member is made from a material selected from the group of materials consisting of natural rubber, polybutadiene, polyisoprene and styrene butadiene. Alternatively the unitary resilient member may be comprised of a combination of materials selected from the group of materials consisting of polybutadiene, polyisoprene and styrene butadiene. The base material is reinforced with a carbon black and is cured with sulfur and/or peroxide. Additionally, the unitary resilient member includes an internal lubricant. The lubricant may be comprised of either octadecanoic acid or 9-octadecenamide for example.
The foregoing and other aspects will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawing figures.